Patent Literature 1 discloses a deformed folded dipole antenna. The deformed folded dipole antenna includes a pair of two parallel parts disposed parallel to each other, and short circuit portions having a smaller length than the parallel parts and each connecting the ends of the two parallel parts together. One of the two parallel parts includes a feed point, while the other parallel part does not include a feed point.
The parallel part that does not include a feed point (hereinafter, non-feed side parallel part) has a shape in which three sides are connected at right angles. Specifically, the non-feed side parallel part includes a pair of opposite sides disposed opposite each other, and a connecting side that connects the pair of opposite sides together at one end thereof.
On the other hand, the parallel part that includes a feed point (hereinafter, feed-side parallel part) has a shape that includes a pair of L-shaped portions. Specifically, the feed-side parallel part includes an L-shaped portion that faces part of one opposite side and part of the connecting side of the non-feed side parallel part, and an L-shaped portion that faces part of the other opposite side and part of the connecting side of the non-feed side parallel part. In other words, the feed-side parallel part includes two L-shaped portions.
Patent Literature 1 also discloses a method of adjusting impedance of the deformed folded dipole antenna. Patent Literature 1 discloses a method of adjusting impedance, wherein W1 to W4 are defined as follows and W1 to W4 are adjusted to have specific relationships with each other.
W1 to W4 are defined as follows. W1 is a width of parts of the two L-shaped portions that face the opposite sides. W2 is a width of parts of the two L-shaped portions that face the connecting side. W3 is a width of the opposite sides of the non-feed side parallel part. W4 is a width of the connecting side of the non-feed side parallel part.
Patent Literature 1 also discloses that, by adjusting the widths W1 to W4 such that W2>W1, W3, and W4, for example, an increase in the size of the antenna can be reduced. Nevertheless, a further reduction in size of deformed folded dipole antennas is desired in cases where the antenna is mounted on a portable device or the like.